Re: [PATCH 11/14] media: medkatek: vcodec: covert secure fd to secure handle

From: Nicolas Dufresne
Date: Tue Sep 19 2023 - 15:43:16 EST


Le lundi 11 septembre 2023 à 20:59 +0800, Yunfei Dong a écrit :
> User driver will fill or parse data in optee-os with secure handle,
> need to covert secure fd to secure handle in kernel.
>
> Signed-off-by: Yunfei Dong <yunfei.dong@xxxxxxxxxxxx>
> ---
> .../vcodec/decoder/mtk_vcodec_dec_drv.c | 1 +
> .../vcodec/decoder/mtk_vcodec_dec_stateless.c | 54 ++++++++++++++++++-
> drivers/media/v4l2-core/v4l2-ctrls-defs.c | 5 ++
> include/uapi/linux/v4l2-controls.h | 4 ++
> 4 files changed, 62 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_drv.c b/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_drv.c
> index 0a89ce452ac3..64e006820f43 100644
> --- a/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_drv.c
> +++ b/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_drv.c
> @@ -571,3 +571,4 @@ module_platform_driver(mtk_vcodec_dec_driver);
>
> MODULE_LICENSE("GPL v2");
> MODULE_DESCRIPTION("Mediatek video codec V4L2 decoder driver");
> +MODULE_IMPORT_NS(DMA_BUF);
> diff --git a/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_stateless.c b/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_stateless.c
> index 2ea517883a86..d2b09ce9f1cf 100644
> --- a/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_stateless.c
> +++ b/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_stateless.c
> @@ -426,6 +426,46 @@ static int mtk_vcodec_get_pic_info(struct mtk_vcodec_dec_ctx *ctx)
> return ret;
> }
>
> +static int mtk_dma_contig_get_secure_handle(struct mtk_vcodec_dec_ctx *ctx, int fd)
> +{
> + int secure_handle = 0;
> + struct dma_buf *buf;
> + struct dma_buf_attachment *dba;
> + struct sg_table *sgt;
> + struct device *dev = &ctx->dev->plat_dev->dev;
> +
> + buf = dma_buf_get(fd);
> + if (IS_ERR(buf)) {
> + mtk_v4l2_vdec_err(ctx, "dma_buf_get fail fd:%d", fd);
> + return 0;
> + }
> +
> + dba = dma_buf_attach(buf, dev);
> + if (IS_ERR(dba)) {
> + mtk_v4l2_vdec_err(ctx, "dma_buf_attach fail fd:%d", fd);
> + goto err_attach;
> + }
> +
> + sgt = dma_buf_map_attachment(dba, DMA_BIDIRECTIONAL);
> + if (IS_ERR(sgt)) {
> + mtk_v4l2_vdec_err(ctx, "dma_buf_map_attachment fail fd:%d", fd);
> + goto err_map;
> + }
> + secure_handle = sg_dma_address(sgt->sgl);

Does it mean if your secure dmabuf is passed to a driver that didn't know it was
secure it will pick the handle as a memory address and program the HW with it ?
That seems unsafe, the handle should be stored in a dedicated place and mapping
should either fail, or provide a dummy buffer.

> +
> + dma_buf_unmap_attachment(dba, sgt, DMA_BIDIRECTIONAL);
> + dma_buf_detach(buf, dba);
> + dma_buf_put(buf);
> +
> + return secure_handle;
> +err_map:
> + dma_buf_detach(buf, dba);
> +err_attach:
> + dma_buf_put(buf);
> +
> + return 0;
> +}
> +
> static int mtk_vdec_s_ctrl(struct v4l2_ctrl *ctrl)
> {
> struct mtk_vcodec_dec_ctx *ctx = ctrl_to_dec_ctx(ctrl);
> @@ -436,7 +476,7 @@ static int mtk_vdec_s_ctrl(struct v4l2_ctrl *ctrl)
> struct v4l2_ctrl *hdr_ctrl;
> const struct mtk_vcodec_dec_pdata *dec_pdata = ctx->dev->vdec_pdata;
> const struct mtk_video_fmt *fmt;
> - int i = 0, ret = 0;
> + int i = 0, ret = 0, sec_fd;
>
> hdr_ctrl = ctrl;
> if (!hdr_ctrl || !hdr_ctrl->p_new.p)
> @@ -489,6 +529,12 @@ static int mtk_vdec_s_ctrl(struct v4l2_ctrl *ctrl)
> return -EINVAL;
> }
> break;
> + case V4L2_CID_MPEG_MTK_GET_SECURE_HANDLE:
> + sec_fd = ctrl->val;
> +
> + ctrl->val = mtk_dma_contig_get_secure_handle(ctx, ctrl->val);
> + mtk_v4l2_vdec_dbg(3, ctx, "get secure handle: %d => 0x%x", sec_fd, ctrl->val);
> + break;
> default:
> mtk_v4l2_vdec_dbg(3, ctx, "Not supported to set ctrl id: 0x%x\n", hdr_ctrl->id);
> return ret;
> @@ -525,8 +571,9 @@ static const struct v4l2_ctrl_ops mtk_vcodec_dec_ctrl_ops = {
> static int mtk_vcodec_dec_ctrls_setup(struct mtk_vcodec_dec_ctx *ctx)
> {
> unsigned int i;
> + struct v4l2_ctrl *ctrl;
>
> - v4l2_ctrl_handler_init(&ctx->ctrl_hdl, NUM_CTRLS);
> + v4l2_ctrl_handler_init(&ctx->ctrl_hdl, NUM_CTRLS + 1);
> if (ctx->ctrl_hdl.error) {
> mtk_v4l2_vdec_err(ctx, "v4l2_ctrl_handler_init failed\n");
> return ctx->ctrl_hdl.error;
> @@ -543,6 +590,9 @@ static int mtk_vcodec_dec_ctrls_setup(struct mtk_vcodec_dec_ctx *ctx)
> }
> }
>
> + ctrl = v4l2_ctrl_new_std(&ctx->ctrl_hdl, &mtk_vcodec_dec_ctrl_ops,
> + V4L2_CID_MPEG_MTK_GET_SECURE_HANDLE, 0, 65535, 1, 0);
> +
> v4l2_ctrl_handler_setup(&ctx->ctrl_hdl);
>
> return 0;
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls-defs.c b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> index 8696eb1cdd61..d8cf01f76aab 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> @@ -1041,6 +1041,7 @@ const char *v4l2_ctrl_get_name(u32 id)
> case V4L2_CID_MPEG_VIDEO_HEVC_SIZE_OF_LENGTH_FIELD: return "HEVC Size of Length Field";
> case V4L2_CID_MPEG_VIDEO_REF_NUMBER_FOR_PFRAMES: return "Reference Frames for a P-Frame";
> case V4L2_CID_MPEG_VIDEO_PREPEND_SPSPPS_TO_IDR: return "Prepend SPS and PPS to IDR";
> + case V4L2_CID_MPEG_MTK_GET_SECURE_HANDLE: return "MediaTek Decoder get secure handle";
>
> /* AV1 controls */
> case V4L2_CID_MPEG_VIDEO_AV1_PROFILE: return "AV1 Profile";
> @@ -1437,6 +1438,10 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
> case V4L2_CID_MPEG_VIDEO_VPX_NUM_REF_FRAMES:
> *type = V4L2_CTRL_TYPE_INTEGER_MENU;
> break;
> + case V4L2_CID_MPEG_MTK_GET_SECURE_HANDLE:
> + *type = V4L2_CTRL_TYPE_INTEGER;
> + *flags |= V4L2_CTRL_FLAG_WRITE_ONLY;
> + break;
> case V4L2_CID_USER_CLASS:
> case V4L2_CID_CAMERA_CLASS:
> case V4L2_CID_CODEC_CLASS:
> diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
> index c3604a0a3e30..7b3694985366 100644
> --- a/include/uapi/linux/v4l2-controls.h
> +++ b/include/uapi/linux/v4l2-controls.h
> @@ -954,6 +954,10 @@ enum v4l2_mpeg_mfc51_video_force_frame_type {
> #define V4L2_CID_MPEG_MFC51_VIDEO_H264_ADAPTIVE_RC_STATIC (V4L2_CID_CODEC_MFC51_BASE+53)
> #define V4L2_CID_MPEG_MFC51_VIDEO_H264_NUM_REF_PIC_FOR_P (V4L2_CID_CODEC_MFC51_BASE+54)
>
> +/* MPEG-class control IDs specific to the MediaTek Decoder driver as defined by V4L2 */
> +#define V4L2_CID_MPEG_MTK_BASE (V4L2_CTRL_CLASS_CODEC | 0x2000)
> +#define V4L2_CID_MPEG_MTK_GET_SECURE_HANDLE (V4L2_CID_MPEG_MTK_BASE+8)
> +
> /* Camera class control IDs */
>
> #define V4L2_CID_CAMERA_CLASS_BASE (V4L2_CTRL_CLASS_CAMERA | 0x900)